EVB RT6259BHGQW-00 EN

RT6259BHGQW
Evaluation Board
your power partner.
3A, 18V, 650kHz, ACOT™ Synchronous Step-Down Converter
Purpose
The RT6259BH are high-performance 650kHz 3A step-down regulators with internal power switches and
synchronous rectifiers. This document explains the function and use of the RT6259BH evaluation board (EVB), and
provides information to enable operation, modification of the evaluation board and circuit to suit individual
requirements.
Table of Contents
Purpose ................................................................................................................................................................. 1
Introduction............................................................................................................................................................ 2
Key Performance Summary Table .......................................................................................................................... 2
Bench Test Setup Conditions ................................................................................................................................. 3
Schematic, Bill of Materials & Board Layout ........................................................................................................... 5
More Information.................................................................................................................................................... 8
Important Notice for Richtek Evaluation Board ....................................................................................................... 8
EVB_RT6259BHGQW-00
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2016
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RT6259BHGQW
Evaluation Board
your power partner.
Introduction
General Product Information
The RT6259BH are high-performance 650kHz 3A step-down regulators with internal power switches and
synchronous rectifiers. The feature quick transient response using Advanced Constant On-Time (ACOT™) control
architecture that provides stable operation with small ceramic output capacitors and without complicated external
compensation, among other benefits. The input voltage range is from 4.5V to 18V and the output is adjustable from
0.765V to 7V. The proprietary ACOT™ control improves upon other fast response constant on-time architectures,
achieving nearly constant switching frequency over line, load, and output voltage ranges. Since there is no internal
clock, response to transients is nearly instantaneous and inductor current can ramp quickly to maintain output
regulation without large bulk output capacitance. The RT6259BH are stable with and optimized for ceramic output
capacitors. With internal 70mΩ switches and 70mΩ synchronous rectifiers, the RT6259BH display excellent
efficiency and good behavior across a range of applications, especially for low output voltages and low duty cycles.
Cycle-bycycle current limit, input under-voltage lock-out, externallyadjustable soft-start, output under- and
over-voltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions. The
RT6259BH is available in WQFN-16L 3x3 package, with exposed thermal pads.
Product Feature
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Fast Transient Response
Steady 650kHz Switching Frequency at all Load Current
3A Output Current
Advanced Constant On-Time (ACOT™) Control
Optimized for Ceramic Output Capacitors
4.5V to 18V Input Voltage Range
Internal 70mΩ Switch and 70mΩ Synchronous Rectifier
0.765V to 7V Adjustable Output Voltage
Externally-adjustable, Pre-biased Compatible Soft-Start
Cycle-by-Cycle Current Limit
Optional Output Discharge Function
With Hiccup Mode Output Over- and Under-voltage Shut-down protection
Input Under-Voltage Lockout
Thermal Shutdown
Key Performance Summary Table
Key Features
Evaluation Board Number : PCB033_V1
Input Voltage Range
4.5V to 18V
Max Output Current
3A
Default Output Voltage
1.05V
Default Marking & Package Type
RT6259BHGQW, WQFN-16L 3x3
Operation Frequency
Fixed 650kHz
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2016
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Bench Test Setup Conditions
Headers Description and Placement
Please carefully inspect the EVB IC and external components, comparing them to the following Bill of Materials, to ensure that all components are
installed and undamaged. If any components are missing or damaged during transportation, please contact the distributor or send e-mail to
[email protected].
Test Points
The EVB is provided with the test points and pin names listed in the table below.
Test point/
Pin name
Signal
Comment (expected waveforms or voltage levels on test points)
VIN
Input voltage
Power input.
EN
Enable test point
Externally pulled high to enable and pulled low to disable this
chip. It is internally pulled up to high when the pin is floating.
GND
Ground
The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
VREG5
Internal Regulator Output
Internal Regulator Output. Connect a 1µF capacitor to GND to
stabilize output voltage.
SS
Soft-Start Control
Connect an external capacitor between this pin and GND to set
the soft-start time.
PG
Power good test point
Output of power good indicator.
BOOT
Bootstrap supply test point
Bootstrap supply for high-side gate driver. Connect a capacitor
between the BOOT and SW pins.
SW
Switch node test point
Connect this pin to an external L-C filter.
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Power-up & Measurement Procedure
1. Apply a 12V nominal input power supply (4.5 < VIN < 18V) to the VIN and GND terminals.
2. Set the jumper at JP2 to connect terminals 2 and 3, connecting EN to enable operation.
3. Set the jumper at JP1 to connect terminals 1 and 2, power VCC pin by VIN voltage source.
4. Verify the output voltage (approximately 1.05V) between VOUT and GND.
5. Connect an external load up to 3A to the VOUT and GND terminals and verify the output voltage and current.
Output Voltage Setting
Set the output voltage with the resistive divider (R2, R3) between VOUT and GND with the midpoint connected to
FB. The output is set by the following formula :
VOUT = 0.765 × (1 +
EVB_RT6259BHGQW-00
R2
)
R3
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Schematic, Bill of Materials & Board Layout
EVB Schematic Diagram
Bill of Materials
Reference
Qty
Part Number
Description
Package
Manufacture
U1
1
RT6259BHGQW
DC/DC Converter
WQFN-16L 3x3
RICHTEK
C2, C6, C8, C12
4
C1608X7R1H104KT000N
0.1µF/50V/X7R
C-0603
TDK
C3, C4
2
GRM31CR71E106KA12L
10µF/25V/X7R
C-1206
MURATA
C5
1
C2012X7R1H105KT
1µF/50V/X7R
C-0805
TDK
C7
1
0603B332K500
3.3nF/50V/X7R
C-0603
WALSIN
C9, C10
2
C3225X5R1E226MT
22µF/25V/X7R
C-1210
TDK
C1, C11, C13,
C14, R6, R7
6
L1
1
NR8040T1R4N
1.4µH/7A
8 x 8 x 4 mm
TAIYO
YUDEN
R1
1
0603 JUMP
0Ω
R-0603
R2
1
0603 8K25 1%
8.25k
R-0603
R3
1
0603 22K1 1%
22.1k
R-0603
R4, R5
2
0603 100K 1%
100k
R-0603
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PCB Layout
Top View (1st layer)
PCB Layout—Inner Side (2nd Layer)
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PCB Layout—Inner Side (3rd Layer)
Bottom View (4th Layer)
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2016
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More Information
For more information, please find the related datasheet or application notes from Richtek website
http://www.richtek.com.
Important Notice for Richtek Evaluation Board
THIS DOCUMENT IS FOR REFERENCE ONLY, NOTHING CONTAINED IN THIS DOCUMENT SHALL BE CONSTRUED AS RICHTEK’S WARRANTY, EXPRESS
OR IMPLIED, UNDER CONTRACT, TORT OR STATUTORY, WITH RESPECT TO THE PRESENTATION HEREIN. IN NO EVENT SHALL RICHTEK BE LIABLE T O
BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL
DAMAGES.
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2016
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